Kak rabotaet setExpectedJavaScriptAlert(String s), setExpectedJavaScriptAlert(String[] s)?

Vot takoi kod:

1 tester.setExpectedJavaScriptAlert("Invalid Email");
2 tester.submit();
3 tester.setTextField("password","12345");
4 tester.setExpectedJavaScriptAlert("Invalid Password");
5 tester.submit();

I na stroke 4 proishodit oshibka

junit.framework.AssertionFailedError: You previously tell that alert with message [Invalid Email]
was expected, but nothing appeared.

Esli ia rabotau setExpectedJavaScriptAlert(String[] s), to proishodit toje samoe

Kak v odnom teste proverit neskolko raznih JavaScript soobschenii?